Disposable absorbent sanitary article with stretchable longitudinal seals forming a pouch

ABSTRACT

A disposable diaper with stretchable longitudinal seals. The diaper includes an absorbent pad between a liquid-tight outer backing sheet and a liquid-pervious inner surface sheet including an elongate opening. Two first longitudinal folds extend over the length of the diaper on either side of the longitudinal opening so that each fold defines a closed sleeve including a stretched resilient member. At least two additional longitudinal folds extend over the length of the diaper and are arranged between the first longitudinal folds and a longitudinal region in which the surface sheet is attached to the diaper.

TECHNICAL FIELD Background of the Invention

In general terms, the invention relates to a disposable absorbentsanitary article, such as an open disposable absorbent diaper intendedfor young children or incontinent adults, or a disposable absorbentdiaper intended for the toilet-training of children, of the typecomprising an absorbent pad placed between a liquid-tight outer backingsheet and a liquid-pervious inner surface or covering sheet.

The invention relates more particularly to a disposable absorbentsanitary article of this type whose inner surface sheet includes anelongate longitudinal opening, for receiving the urine and stools, andat least two elasticated longitudinal folds extending over the wholelength of said sanitary article on either side of the longitudinalopening so as to form a leaktight, exudate-containing pouch.

Sanitary articles of this type are known, for example, from U.S. Pat.No. 4,662,877 (Johnson & Johnson). According to that document, the innersurface sheet of the sanitary article is hydrophobic and is providedwith an elongate opening which is offset toward the front of thearticle. The longitudinal edges of the opening are provided withresilient elements which are fixed in the stretched state.

French patent application FR-A-9210601 (Peaudouce) also describes adiaper whose inner surface sheet includes an elongate central openingand two elasticated longitudinal double folds extending over the wholelength of the diaper and located on either side of the central opening.The two pleats of each double fold are secured to each other over thewhole length of the double folds.

French patent application FR-93 14 296 (Peaudouce), which has not beenpublished, also describes a diaper of the same type, with the doublefolds being capable of being folded outwards in a longitudinal regionextending from the front transverse edge of the opening as far as thefront transverse edge of the diaper, so as to form small longitudinalseals to prevent urine leaking out.

European patent application EP-A-357 298 (The Procter and GambleCompany) describes a diaper whose urine-pervious surface sheet includesa passage which permits the communication of fecal matter with theabsorbent pad so as to isolate said matter from the user's skin. Thispassage is an oblong opening which is slightly offset toward the rear ofthe article. Resilient elements are fixed to the surface sheet close tothe opening to cause the surface sheet to contract.

European patent applications EP-A-508 477, EP-A-563 971, EP-A-565 058and EP-A-567 105 (Uni-Charm Corporation) also describe diapers whoseinner surface sheet includes an elongate central opening, this centralopening being capable of having one or two pairs of lateral longitudinalflaps whose free edges may be elasticated.

Although these structures described in the prior art are relativelyeffective, it would still be desirable to improve the take-up andisolation of bodily exudates, such as stools and urine, and also toimprove the leak-tightness to prevent risks of transverse leaks ofurine. The object of the invention is therefore to provide a disposableabsorbent sanitary article which not only provides better take-up andstorage of exudates but also improved leaktightness to preventtransverse leaks of urine.

SUMMARY OF THE INVENTION

According to the invention, a disposable absorbent sanitary article,such as a diaper, is produced, said article comprising a liquid-tightouter backing sheet of generally rectangular shape, an absorbent pad ofgenerally rectangular shape fixed on said outer backing sheet, and of aliquid-pervious inner surface sheet covering the absorbent pad. Thisinner surface sheet is fixed over its periphery to the outer backingsheet. The sanitary article also comprises fastening means to enable itto be closed around a user's waist.

The article also comprises longitudinal resilient elements fixed in thestretched state to the backing sheet outside the longitudinal edges ofthe absorbent pad, at least in a crotch region.

The liquid-pervious inner surface sheet has a longitudinal opening ofgenerally oblong or elongate shape which is centered on the absorbentpad and narrower than the latter. The inner surface sheet is alsodirectly or indirectly fixed to the absorbent pad, except in a regionlocated below the opening, which is preferably larger than the openingso as to form a continuous containment pouch above the absorbent padwhich comprises two longitudinal sealing flaps, extended by twotransverse flaps, the free edges of which are formed by the edges of thelongitudinal opening.

The inner surface sheet also comprises at least two first longitudinalfolds which are substantially parallel to the median longitudinal axisof the article and extend over the whole length of said article oneither side of the longitudinal opening, forming closed tubular sleevesin which at least one longitudinal resilient element is fixed, in thestretched state.

According to the invention, the inner surface sheet has at least twoadditional longitudinal folds extending over the whole length of thearticle and arranged respectively between each of the first longitudinalfolds and the corresponding lateral longitudinal region in which theinner surface sheet is fixed to the rest of the article. According to apreferred embodiment, each of these additional folds is secured to theinner surface sheet at each of its longitudinal ends, close to thetransverse edges of the article, in a first, shorter region; each ofthese folds is free to unfold in a second region correspond to thegreater part of the length of the article. Since these additional foldsare free to unfold over practically their whole length through theaction of the first elasticated folds which lift the surface sheet alongthe longitudinal edges of the opening, a substantial increase in theheight of the longitudinal sealing flaps is thus obtained and,therefore, better adaptation of said longitudinal flaps to the user'sbody, which gives rise to an improvement in the anti-leak efficiency ofthe containment pouch whilst preserving the same width of the opening.Without the presence of these additional folds, the only other solutionfor increasing the height of the longitudinal flaps of such acontainment pouch would be reducing the width of the opening, but thiswould be to the detriment of optimum adaptation of the opening to theuser's anatomy and of the most effective take-up of the stools and urineby the absorbent pad. In a recommended embodiment, the second region inwhich the additional longitudinal folds are free to unfold extends overa length which is at least equal to that of the crotch region of thesanitary article and preferably at least equal to that of the opening inthe surface sheet. In another recommended embodiment, the closed sleevesof the first longitudinal folds are folded inward in the direction ofthe longitudinal axis of the sanitary article and fixed to the partlying under the inner surface sheet, for example over their whole lengthor intermittently, so as to form Z-shaped folds.

According to another preferred embodiment, the additional longitudinalfolds are produced by means of Z- or S-shaped folding.

According to another variant embodiment, the absorbent sanitary articlealso includes a liquid-pervious intermediate sheet located between theabsorbent pad and the inner surface sheet, this intermediate sheetcovering the pad at least in the region of the longitudinal opening andbeing fixed to the absorbent pad. This intermediate sheet, fixed to thepad, also preferably extends over the whole length of the absorbentsanitary article and is wider than the longitudinal opening. The innersurface sheet can then be fixed to the intermediate sheet, except, asabove, for a region located under the opening.

BRIEF DESCRIPTION OF THE FIGURES

The remainder of the description, which relates to an illustrative andnon-limiting embodiment of the invention, relates to the appendedfigures which show, respectively:

FIG. 1, a perspective top view of a diaper according to the presentinvention;

FIG. 2, a diagrammatic sectional view along the line II--II of FIG. 1;

FIG. 3, a diagrammatic sectional view along the line III--III of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 to 3, the diaper shown comprises, in a mannerknown per se, a liquid-tight backing sheet 1, for example a polyethylenefilm, an absorbent pad 2, for example made from cellulose fluff pulpwith the possible incorporation of particles of superabsorbent material,and a liquid-pervious inner surface sheet 3, for example made fromnonwoven web which is hydrophilic or treated so as to have hydrophobicregions. The two sheets 1 and 3 are the same size and have the samehour-glass shape, i.e. a rectangular shape with two opposite lateralnotches defining, in the direction of the lengths of the diaper, anarrower crotch region 20 between two wider front 21 and rear 22 endregions whose transverse edges define the front and rear transverseedges of the diaper.

The absorbent pad 2 placed between the sheets 1 and 3 is T-shaped, butany other shape may be envisaged. The two sheets 1 and 3 are joinedtogether, for example by bonding, over the periphery of the pad 2.Fastening means 4 are provided to enable the diaper to be closed arounda user's waist.

Longitudinal resilient elements 5 each consisting, for example, of oneor more resilient strands or threads are fixed in the stretched state tothe backing sheet 1, at least in the crotch region, between thelongitudinal edge of the sheet 1 and the corresponding longitudinal edgeof the absorbent pad 2.

As FIG. 1 shows, the inner surface sheet 3 includes an opening 6 whichis generally oblong or elongate in shape and is symmetrical with respectto the median longitudinal axis of the diaper, centered above theabsorbent pad 2 and narrower than the width of the absorbent pad in thecrotch region so as to facilitate the penetration of urine and stoolsinto the pad. This opening is preferably narrower than half the width ofthe pad 2 in the crotch region.

Quite obviously the dimensions of this opening 6 depend on the size ofthe user for which the diaper is intended. In an embodiment given by wayof example, in the case of a so-called "maxi"-size diaper (8-18 kg), theopening 6 is substantially rectangular and has a length of 300 mm and awidth of 50 mm.

The diaper preferably includes a liquid-pervious intermediate strip orsheet 7, for example made from hydrophilic nonwoven, extending over thewhole length of the diaper and equal in width to or wider than the widthof the absorbent pad 2 in the crotch region and thus also wider than thewidth of the longitudinal opening 6. Moreover, this intermediate sheet 7could also be shorter than the diaper and shorter even than theabsorbent pad provided it is longer than the opening 6 so as to avoidany direct contact between the skin of the user and the absorbent pad.This intermediate sheet is preferably fixed to the absorbent pad 2. Theinner surface sheet 3 is fixed, on the one hand, to this intermediatesheet 7 by bonding lines 15, and, on the other hand, to the rest of thediaper by bonding regions 11, except for a region which is located belowthe longitudinal opening 6 and is larger than it (for example, in thecase of the dimensions of the longitudinal opening 6 which were givenabove, this region may be a rectangular region 360 mm in length and 100mm in width), so as to form a continuous containment pouch above and atthe periphery of the absorbent pad, comprising two longitudinal sealingflaps 8 extending via two transverse flaps, the free edges of which areformed by the edges of the opening 6.

The surface sheet 3 also includes two parallel longitudinal folds 9extending over the whole length of the diaper and arranged on eitherside of the longitudinal opening 6 close to the latter's longitudinaledges. The lower edges of the folds 9 are joined by a longitudinalfixing line, for example a bonding line, over the whole length of thefolds, so as to form closed sleeves. Longitudinal resilient elements 10are placed, in the stretched state, inside the folds in the upper partof the closed sleeves formed by these folds 9. These folds maypreferably be folded toward the inside of the diaper in the direction ofthe latter's median longitudinal axis and be fixed to the part lyingunder the inner surface sheet 3, for example by a continuous orintermittent bonding line, so as to form Z- or S-shaped double folds.

The surface sheet 3 also has two additional longitudinal folds 12extending over the whole length of the diaper and arranged symmetricallywith respect to the opening 6 between the first folds 9 and thelongitudinal regions in which the surface sheet 3 is fixed to theintermediate sheet 7 covering the absorbent pad 2 and to the rest of thediaper.

These additional folds 12 may be obtained by means of a process offolding the surface sheet 3, identical to that used to form the firstfolds 9, or by means of any other process, and may, for example, havethe Z-shape as shown in FIGS. 1 to 3. Other types of folding, however,such as, for example, concertina pleating or S-type folding, may beenvisaged.

As shown in FIG. 3, each of these additional folds 12 is secured to thesurface sheet 3 at its longitudinal ends close to the transverse edgesof the diaper, for example by one or more bonding regions 13 or by anyother fixing means (heat sealing, ultrasound) of reduced length, forexample from 1 to 2 cm, also enabling the two faces of the fold to besealed together. In this way, the ends of the folds 12 which could formchannels via which urine escapes to the outside of the diaper areclosed, thereby preventing risks of leaks longitudinally along thesefolds.

On the other hand, each fold 12 is free to unfold over the greater partof its length, i.e. over a length which is at least equal to that of thecrotch region of the diaper and is preferably at least equal to that ofthe opening 6.

The formation of a multiplicity of additional folds distributed over thewidth of each sealing flap 8 may also be envisaged.

When the diaper is placed on the user's body, through the action of thelongitudinal resilient elements 10 fixed in the first folds 9, whichraise the edges of the opening 6 of the surface sheet 3, unfolding ofthe folds 12 gives rise to an increase in the height of the longitudinalsealing flaps 8 and thus better adaptation of the latter to the user'sbody without the width of the opening 6 being modified during themanufacturing process. Indeed, as the height of each longitudinalsealing flap 8 forming the greater part of the containment pouch isdefined by the distance between the corresponding longitudinal edge ofthe opening 6 and the longitudinal line 15 for fixing the surface sheet3 to the intermediate sheet 7, if this line 15 cannot be shifted towardthe longitudinal edges of the diaper for reasons of leaktightness theonly possibility which remains at the manufacturing-process level is toreduce the width of the opening 6. In point of fact, such a reductioncan only be detrimental to satisfactory take-up and efficient storage ofstools and urine.

A diaper which allows better leaktightness on the part of thecontainment pouch thus formed with respect to leaks of urine is thusproduced, while still maintaining excellent take-up and retention ofurine and stools in the absorbent pad.

I claim:
 1. A disposable diaper having a median longitudinal axis and alongitudinal length and defined by longitudinal and transverse edges,said diaper further comprising:a liquid-tight outer backing sheet ofgenerally rectangular shape, an absorbent pad of generally rectangularshape with a periphery defined by longitudinal edges and transverseedges, said absorbent pad being fixed on said outer backing sheet, aliquid-pervious inner surface sheet covering the absorbent pad, aperiphery of the liquid-pervious inner surface sheet being fixed to theouter backing sheet, fastening means to enable the diaper to be closedaround a user's waist, longitudinal resilient elements fixed in astretched state to the backing sheet outside the longitudinal edges ofthe absorbent pad, at least in a crotch region of the diaper, said innersurface sheet including a longitudinal opening which is centered on theabsorbent pad and narrower than the absorbent pad, said inner surfacesheet being fixed to the absorbent pad, except in a region which islocated below the longitudinal opening, said region being larger thanthe longitudinal opening so as to form a containment pouch above and atthe periphery of the absorbent pad, said inner surface sheet furtherincluding at least two first longitudinal folds which are substantiallyparallel to the longitudinal opening, each of said folds forming aclosed sleeve in which at least one longitudinal resilient element isfixed, in a stretched state, and said inner surface sheet furtherincluding at least two additional longitudinal folds with longitudinalends extending over the longitudinal length of the diaper and arrangedlaterally respectively between each of the first longitudinal folds anda corresponding lateral longitudinal region in which the inner surfacesheet is fixed to the diaper; wherein each of the at least twoadditional longitudinal folds is secured to the inner surface sheet ateach of the longitudinal ends, close to the transverse edges of thediaper, in a first, shorter region, and each of the at least twoadditional folds being configured so as to be free to unfold in a secondregion corresponding to a greater part of the longitudinal length of thediaper.
 2. The diaper according to claim 1, wherein the second region inwhich the at least two additional longitudinal folds are free to unfoldextends over a length which is at least equal to that of the crotchregion of the diaper.
 3. The diaper according to claim 1, wherein theclosed sleeves of the first longitudinal folds are folded inward in thedirection of the longitudinal axis of the diaper and fixed to a partlying under the inner surface sheet so as to form Z-shaped folds.
 4. Thediaper according to claim 1, wherein the at least two additionallongitudinal folds are produced by means of Z- or S-shaped folding. 5.The diaper according to claim 1, further comprising a liquid-perviousintermediate sheet located between the absorbent pad and the innersurface sheet, said intermediate sheet covering the absorbent pad atleast in the region of the longitudinal opening and being fixed to theabsorbent pad.
 6. The diaper according to claim 5, wherein saidintermediate sheet extends over the longitudinal length of the diaperand is wider than the longitudinal opening and the inner surface sheetis fixed to said intermediate sheet, except for said region locatedbelow the opening which is larger than the longitudinal opening.
 7. Thediaper according to claim 1, wherein the second region in which the atleast two additional longitudinal folds are free to unfold extends overa length which is at least equal to that of the longitudinal opening inthe inner surface sheet.